Hi Is it possible to calculate length and orientation of force vector for atom or group of atoms from trajectory obtained Sincerely yours, Dima Ph.D. Student Dmitry Kovalsky Institute of Molecular Biology & Genetics 150 Akad. Zabolotnogo Street, Kiev-143, 03143 UKRAINE E-mail: dikov at imbg.org.ua Fax: +380 (44) 266-0759 Tel.: +380 (44) 266-5589